The term SPECTROSCOPE PART can be solved by the crossword solution PRISM, which is a five-letter word. A PRISM is a transparent optical element with flat, polished surfaces that refract light. In spectroscopy, prisms are used to disperse light into its component wavelengths, allowing for the study of the spectrum of light emitted from a given source. Prisms are also used in spectroscopes, which are instruments used to measure and analyze the properties of light.